Date of Award
Open Access Thesis
Master of Science (MS)
Dr. Christine Maher
Andrew Anderson, Dean
Migration into seawater from freshwater, freshwater and estuary habitat residency
Life histories of anadromous fish are difficult to examine due to constraints on direct observation. However, an understanding of patterns of habitat use is critical to management efforts since recruitment to spawning age is vital to population sustainability. Blueback herring (Alosa aestivalis) are anadromous fish that utilize a variety of freshwater, estuary and nearshore marine habitats. Rapid declines in their abundance and a subsequent petition for listing under the US Endangered Species Act in 2012 have ushered in an immediate need for life history information. This study focused on five river systems and seven spawning runs along the coast of Maine, USA. Systems with greater areas of freshwater and/or estuary were predicted to support young fish for a greater portion of the life cycle based on advantages provided by low to no salinity nursery habitat. I used otolith microchemistry and ambient water concentrations of Ca, Ba and Sr within fresh, estuarine and marine waters to identify habitat use in 131 returning adult fish collected during the spawning runs of 2010 and 2012.
Wynne, Molly Payne, "Retrospective Examination of Habitat Use by Blueback Herring (Alosa aestivalis) Using Otolith Microchemical Methods" (2014). All Theses & Dissertations. 193.